FUNDAMENTALS OF TRAFFIC FLOW and TRAFFIC ENGINEERING

Question 1

the rate of movement of traffic is expressed in metric units in
kilometers per hour (kph)

Answer 1

SPEED

Question 2

is the number of vehicles per unit length of the road at that
instant is expressed as the number of vehicles per lane-km of the road.

Answer 2

DENSITY

Question 3

is a measure to quantify the traffic flow. Expressed as the
number of vehicles that pass across a given transverse line of the road during
unit time.

Answer 3

VOLUME

Question 4

Rate of traffic, vehicle per hour (vph); equivalent hourly rate

Answer 4

FLOW

Question 5

BASIC ELEMENTS OF HIGHWAY TRAFFIC ANALYSIS

Answer 5

• The quantity of traffic
• The type of vehicles within the traffic stream
• The distribution of flow over a period of time (usually 24 hours)
• The average speed of the traffic stream
• The density of the traffic flow.

Question 6

a measure of the volume of traffic on a highway, is defined as the
number of vehicles, , passing some given point on the highway in a given time
interval, , i.e.:

Answer 6

TRAFFIC FLOW

Question 7

measure of the number of vehicles, , occupying a
length of roadway, .

Answer 7

TRAFFIC DENSITY

Question 8

the average speed for all
vehicles in a given space at a given discrete point in time

Answer 8

SPACE MEAN SPEED

Question 9

THREE PARAMETERS

Answer 9

SPEED, DENSITY, AND TRAFFIC FLOW

Question 10

the arithmetic mean of the speeds of vehicles passing a point
on a highway during an interval of time

Answer 10

TIME MEAN SPEED

Question 11

the difference between the time the front of a vehicle arrives at
a point on the highway and the time the front of the next vehicle arrives at that same
point. Time headway is usually expressed in seconds.

Answer 11

TIME HEADWAY

Question 12

e distance between the front of a vehicle and the front of the
following vehicle and is usually expressed in meters.

Answer 12

SPACE HEADWAY

Question 13

is a system of notation according to which the various
characteristics of a queuing model are identified.

Answer 13

KENDALL’S NOTATION

Question 14

s the maximum hourly rate at which persons or vehicles can
reasonably be expected to traverse a point or uniform section of a lane or roadway
during a given time period under prevailing roadway, traffic, and control conditions.

Answer 14

CAPACITY

Question 15

a qualitative description of how a
certain facility is performing.

Answer 15

LEVEL OF SERVICE

Question 16

determine the
width and number of lanes when planning for new facilities or when expanding
existing facilities that are already experiencing congestion problems.

Answer 16

CAPACITY AND LEVEL OF SERVICE

Question 17

developed by the Planning
Service of the DPWH provides a methodology to carry out the process of such analysis.

Answer 17

PHILIPPINE HIGHWAY PLANNING MANUAL (PHPM)

Question 18

uses qualitative measures that characterize operational
conditions within a traffic stream and perception of these conditions by motorists and
passengers.

Answer 18

LOS CONCEPT

Question 19

how many levels of service are there

Answer 19

SIX LEVELS OF SERVICE

Question 20

Free flow, with low volumes and high speeds. Drivers are virtually
unaffected by the presence of others. Little or no restriction in
maneuverability and speed.

Answer 20

LEVEL A

Question 21

The level of comfort and convenience provided is somewhat
less than at LOS A. Zone of stable flow with operating speeds
beginning to be restricted somewhat by traffic conditions.
Drivers will have reasonable freedom to select their speed but
there is a decline in freedom to maneuver within the traffic
stream from LOS A.

Answer 21

LEVEL B

Question 22

Still in zone of stable flow, but speed and maneuverability are
most closely controlled by higher volumes. Most of the drivers
are restricted in the freedom to select their own speed, lane
changing, or overtaking maneuvers. The level of comfort and
convenience declines noticeably at this level.

Answer 22

LEVEL C

Question 23

Approaches unstable flow. Speed and freedom to maneuver
are severely restricted, and drivers experience a generally poor
level of comfort and convenience. Small increases in traffic flow
will generally cause operational problems

Answer 23

LEVEL D

Question 24

Flow is unstable, and there may be stoppages of momentary
condition. Represents operating conditions at or near capacity
level. All speeds are reduced to allow but relatively uniform
value. Freedom to maneuver within the traffic stream is
extremely restricted, and it is generally accomplished by forcing
a vehicle to “give way” to accommodate such maneuver

Answer 24

LEVEL E

Question 25

Forced or breakdown flow. The amount of traffic approaching
a point exceeds the amount that can traverse the points.
Queues form behind such locations. Operation within the
queue is characterized by stop-and-go waves and is extremely
unstable. It is the point at which arrival flow causes the queue to
form.

Answer 25

LEVEL F

Question 26

provides ways of assessing the impacts of these activities by
knowing the magnitude of vehicular delay and the extent of queue propagated

Answer 26

QUEUING ANALYSIS

Question 27

characterized by some form of arrival pattern usually given
by its arrival distribution

Answer 27

INPUT

Question 28

generally depends on the queue discipline and
the service mechanism at the service station.

Answer 28

OUTPUT

Question 29

The most common type of queue
discipline. the first one that arrives at the
service station gets served first and therefore the first to leave the system as well

Answer 29

FIFO

Question 30

manner
Input Output
Service
Station
customers are served at the station

Answer 30

SERVICE MECHANISM

Question 31

used for random processes

Answer 31

MARKOV

Question 32

used for processes
that are characterized by regular or constant arrivals or departures

Answer 32

DETERMINISTIC